Note: Descriptions are shown in the official language in which they were submitted.
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It is well~known that washing machines must be equipped
with devices which can lock the door closin~ mechanism when
the machine is started up and then unlock them with a certain
delay after the current has switched off, in order to ensure
that the door cannot be opened while some of the components
are still rotating inertially (in particular the drum of the
spin-dryer).
Some types of these devices exist in which the closing
and delayed opening is obtained by means of the use of a bi-
metal and the time this takes to cool. There are other types
of devices, some of them of the same inventor, which carry
out the aforesaid functions by other means: magnetic, wax
actuated thermostats etc.
The present invention provides a door-locking device
which gives ample guarantees of safety, locking the door
before the washing machine is in motion, maintaining this
lock during the time the machine is operating up to the time
the current is interrupted and beyond this until e~ery
rotating part has stopped.
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In addition, the door-locking device according to this
invention also functions as a series switch connected to the
door in such a way as to ensure that the circuits which
actuate the machine cannot close if the door has not been
completely shut. This series swi~ch has the added advantage
of being in a position which is inaccessible to the user,
thus making it impossible to actuate the machine with the
door open, even if the user wishes to do thisO
A further characteristic of the invention is that the
door-locking device is equipped with an extremely simple and
effective device which regulates the opening time.
Another characteristic of the invention is the
arrangement of its components which makes it possible to
construct and mount the body of the device and subsequently
add to it the eyelet sliding bar into which the hook of the
door-latch and the coupling flange of th~ washing machine
fit. These details vary from manufacturer to manufacturer,
there~ore the same basic standard device can be used for the
most varied types of machines simply by changing these two
specific details (sliding bar and coupling flange).
Finally, it has been designed in such a way that the
basic body of the door-locking device can, when requested, be
connected up to a device which contains the controls of the
moving parts of the machine during the washing stage, or to
the drying controls if the machine also functions as a dryer,
so that the door is not locked during these sequences of the
cycle.
In one aspect the invention provides a device for rapid
locking and delayed unlocking of a door-closing mechanism of
a machine which has internal parts subject to inertial
rotation, such as a door of a washing machine, comprising a
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sliding bar w~rkiny together with a hook of a door latch
associated with a pin sui-table for locking the aforesaid
sliding bar under certain pre- et conditions, characterized
by the fact that the locking pin is actua~ed by a mobile
contact plate of a microswitch, having also the function of a
series switch, by means of a rocker arm moved by a bi-
metallic strip heated by a resistor electrically connacted to
control means of the machine, the mobile contact plate of the
microswitch being in its turn, subjected to a load of an
eccentric ratchet, said load being capable o~, by increasing
or decreasing, adjusting an insertion time and delayed
opening of the door locking device as a ~unction of the
possible variations in curvature or straightening time of the
bi-metallic strip during heating and cooling stages of the
bi~metallic strip and related heating means, variations which
can also occur in materials from the same lot, the heating
means of the bi-metallic strip bsing constituted by a ceramic
thermistor.
Preferred embodiments of this aspect of the invention
are:
The above device, wherein the bi-metallic strip rests on
first supports, the ceramic thermistor rests on the bi-
metallic strip, and the rocker arm rests on the ceramic
thermistor and is held in position only laterally by second
supports thus ensuring that the curvature and straightening
times remain constant through time.
The above device, wherein to ensure exact positioning of
the sliding bar and thus an eyelet thereof during the phases
of opening and locked closiny~ a back part of the sliding bar
is divided into two arms which separate and come together
elastically, each of said arms being provided with lateral
notches situated in such a way as to lock into two wedges
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provided in corresponden~e in the body of the door-locking
device.
The above device, further comprising a flange for
coupling said device to said machine, said flange being
adapted to be compatible with the type and make of machine on
which the device is to be mounted, said flange being moulded
separately from the body of the door locking device, and
being connectable to the body of the door locking device by
means of two slots and two protuberances which can be coupled
respectively to two coupling devices and two clutch jaws
which are provided on the flange.
The above device, wherein said sliding bar being
provided with an eyelet, said eyelet having the appropriate
shape and size for the type and make of machine on which the
device is to be mounted, being interchangeable and being
insertable into a finished door-lock simply from outside.
The above device, wherein said door-locking device being
capable o~ association with a control device which permits
the machine to function during certain sequences of the
working cycl , such as washing or drying, when a drum rotates
slowly, without locking the door-closing mechanism, said
control device being constituted by a box connectable by two
components which can be plugged firmly into protrusions
provided on the outside of the box body of the door-locking
device, said microswitch being activated by means of a push-
button which acts on a mobile contact plate o~ the aforesaid
microswitch and is housed in a hollow cylinder so that one of
said push-buttons protrudes outside the box, said hollow
cylinder being able to be inserted in a hole drilled in the
box body o~ the door-locking device so that the push-button
comes into contact with the sliding bar o~ the door-locking
device which has been provided with a notch situated in such
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a way to receive one end of the push-button when the sliding
bar is in the off position, so that by moving the sliding
bar, pushed by the hook of the door latch of the machine, the
push-button closes the microswitch.
In a further aspect the invention provides for use in
effecting rapid locking and delayed unlocking of door-closing
mechanisms of machines, such as washing machines, which have
internal parts subject to inertial rotation; apparatus of the
type comprising a sliding bar engageable with hook means of a
door latch and including locking pin means suitable for
locking said sliding bar during the rotational part of the
machine cycle, said locking pin means being actuatable by a
mobile contact means of a microswitch functioning as a power
switch for the machine, said mobile contact means of the
microswitch being shiftable by means driven by a single
bimetallic strip suitably heated by a resistor elecrtrically
connected to a power circuit of the machine; the improvement
to said apparatus comprising: a rocker arm interposed
between said bimetallic strip and the mobile contact means of
said microswitch; means engaging said mobile contact means of
said microswitch for increasing or decreasing the load
thereon to adjust the time required for curvature and
straightening movement of said bimetallic strip during its
heating and cooling stages; supports for said bimetallic
strip; said heating resistor being in contact with said
bimetallic strip to be moved thereby; and said rocker arm
being in contact with said resistor; whereby the curvature
and straightening times of said bimetallic strip remain
constant over time.
Preferred embodiments of this aspect of the invention
are:
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The above apparatus, comprising a mounting flange ~or
coupling said apparatus to the machine; said mounting flange
being constructed as an element separate from said apparatus
wheraby a different size and configuration of the flange may
be selected and installed according to the type and make of
machine on which the apparatus is to be mounted; said flange
being formed so as to be connectable to a frame of said
apparatus; said frame being formed with slots and
protuberances to effect coupling with said flange.
The above apparatus, wherein said sliding bar is formed
with an eyelet shaped and sized to receive the hook means of
the machine on which the apparatus is to be mounted, thereby
providing for insertion of the apparatus into the finished
door-lock simply from outside~
~ he above apparatus, further comprising a device
permitting the machine to function during certain sequences
of the working cycle when the rotational parts rotate slowly,
without locking the door-closing mechanism, said device
comprising a box connectable by couplings engageable with
cooperating means provided on the outside of a frame of said
door-locking apparatus, and including a second microswitch
activatable by means of a push-button which acts on the
mobile contact plate of said first microswitch and i5 housed
in means so that it can protrude outside the box, said
housing means being insertable through the frame o~ said
door-locking apparatus so that the push-button can come into
contact with the sliding bar of the door-locking apparatus,
said bar being formed with a notch in position for receiving
one end of said push-button when the sliding bar is in the
off position and the door can be opened and the machine is
stopped with power interrupted by the second microswitch, the
sliding bar, pushed by the hook of the door latch of the
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machine, oparating the push-button to close said second
microswitch.
The invention will now be further described by reference
the drawings, in which:
Figure 1 represents the device at rest, i.e a cross-
section with the door open;
Figure 2 is a view of A-A in fig 1 of the sliding bar which
locks the hook of the door-latch;
0 Figure 3 represents the device in the locked position, i.e
a cross-section with the door closed;
Figure 4 is a view of B-B in fig 3 of the sliding bar which
locks the hook of the door-latch.
Referring to figures 1, 2, 3 and 4, the device according
to the invention is constituted by a boxed body 1 generally
moulded in thermoplastic material, acting as a housing for
the various components of the device, consisting o~:
- a bi-metallic strip 2 resting on supports 3 and 4 made
of electrically conducting materials, support 4 projecting
outside the housing in the form of
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a connection male contact.
- a P.T.C ~Positive Temperature Coefficient) 5, resting with one face on the
bi-metallic strip in such a way as also to constitute an electrical contact
having, when heated, the function of supplying the heat required for the
deformation of the bi-metallic strip;
- a rocker arm 6 made of electrically conducting material, resting on the other
face of the P.T.C 50 as to provide another electrical contact, held in position
laterally by supports 7 and 7' and acting on the mobile contact plate of a
microswitch by means of its upper arms;
- a microswitch constituted by a mobile contact plate 8 connected to the
connection male contact 9 and connected to a eonnection msle contact 11 by
means of a fixed contact 10.
- an eccentric cylindrical component 12 with a toothed section 13 which can
mesh with the pawl 14;
- a sliding bar 15 terminating outside the box 1 in an eyelet 16 into which the
hook of the door-latch 100 is inserted when the door is closed.
A longitudinal cut has been made in the rear half of this sliding bar, opposite
the eyelet, (see figures 2 and 4) and, therefore, the bar 15 is divided into two arms
which come together and separate elastically because of the characteristics of the
material from which they have been made - thermoplastic resin. These arms have
two series OI lateral notches 17 and 17', 18 and 18' which can engage with the
wedges 19 and 19' cut into the body of box 1. This arrangement of the aforesaid part
is designed to avoid the use of springs to keep the sliding bar 15 in the correct
position, both during opening and when locking.
As can be seen in figures 1 and 3, the upper side of the sliding bar 15 has
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another wedge 20 which, as will be explained later, is used for the functioning OI the
machine controls when the door is unlocked.
The sliding bar 15 can be mounted from outside with the door-latch coupled
and is already complete with all its components, so that sliding bar 15 with an eyelet
16 of the appropriate shape and size of the particular make of machine in question
can be mounted;
- a locking pin 21 running in a housing 22, the upper part of which locks into a cavity 23 in the sliding bar 15 during the locking stage.
The lower part of the locking pin 21 has an aperture 24 which accepts the
prolungation 25 of the mobile contact plate 8 of the microswitch.
- a flange 26 which couples the device to the machine of the appropriate form
and size for the particular type and make of machine in question. As has
already been said, this component is not moulded in a single piece with the
body 1, but constitutes an additional interchangeable component.
To implement this, two slots 27 and 27' have been provided in the body 1, to
which can be coupled two arms 28 and 29 protruding from the flange 26 which
is also provided with clutch jaws 30 and 31 which couple to two protusions 32
and 33 contained within the box 1.
The device is completed by contact 34 connected to a connection male
contact 35 which provides the power for an indicator light which remains lit when
the door-lock is not inserted. The door-locking device is electrically connected in
series on the phase of the operating current of the machine. Therefore, while one of
the supply phases goes directly to the working controls of the machine, the second
phase enters through the quick-action contact 9 and passes to the working controls
through the connection male contact 11 with the microswitch 8-11 interposed.
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The connection male contact is provided for the connection of the first phase
of the electricity supply to the P.T.C 5.
The device functions in the following wayO At rest~ the various components
are in the positions shown in figures 1 and 2 i.e. microswitch 8 11 open; bi-metallic
strip 2 in a flat position; sliding bar 15 with eyelet moved forward, in an axis with
the hook 100 of the closing latch of the door, this position of the sliding bar 15 (see
figure 2) being guaranteed by the locking of the wedges 19, 19' into the notches 17
and 17' of the elastic tail of the bar 15.
When the user closes the door (see figure 4) the hook 100 of the door latch
engages with the eyelet 16 and closes, thus pushing the sliding bar 15 backwardsfrom the position shown in figure 2 to the position shown in figure 4 (To be
absolutely accurate, figure 4 shows a transition stage of the movement of the sliding
bar from the open position to the closed position). The bar 15 stops with the wedges
19 and 19' locked into notches 18 and 18' and with the cavity 23 in axis with the pin
21.
At this point 1:he user starts up the machine and the current ~lows through the
connection mal~ contact 9, the mobile contact plate 8, the rocker arm 6, all theelectrically conducting material on one side and, through connection male contact 4,
supplies the P.T.C which heats up almost instantaneously and transmits its heat to
the bi-metallic strip 2, causing it to arch out and thus raise rocker arm 6. Therocker arm 6 acts on the mobile contact plate 8 o~ the microswitch, pressing it
downwards to close the circuit and thus provide power to the working parts o~ the
machine and, at the same time, lowers the pin 21 so that its upper part can insert
itself into the cavity 23 of the sliding bar 15, blocking the bar 15 Ior as long as these
conditions last and, as a consequence, locking the hook 100 of the door latch o~ the
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machine in the eyelet 160
When the machine has completed its working cycle and the current is
interrupted, the P.T.C cools down, the bi-metallic strip returns to the position in
figure 1 and, therefore, the mobile contact plate 8 moves in the opposite direction,
reopening the circuit and, at the same time, raising the pin 21 which withdraws from
the aperture 23 of the sliding bar 15, freeing it and thus permitting the door to open.
During the opening operation, the hook 100 of the door latch moves from the
position shown in figure 3 to the position shown in figure 1, pulling out the locking
bolt and moving it from tne position shown in figures 1 and 3 to the position shown
in figures 2 and 4.
All this does not happen immediately but after a certain lapse of time,
approximately ~0 seconds. This delay is caused by the time required for the
combination of the P.T.C 5 _ bi-metallic strip 2 to cool down, such time being
largely predetermined by the characteristics of the bi-metallic strip and the P.T.~
but, according to this invention, being capable oî adjustment by adjusting the
pressure on the mobile contact plate 8 by means OI the eccentrie ratchet 12 which
can be rotated to achieve the delay required~ such position remaining constant by
means of the hold of the pawl 14 on the teeth 13.
An optional device is now described whose function is to permit the machine
to operate even if the door is not locked. This device can be used in machines which
have the possibility of opening the door during the washing cycle and, therefore, the
door-locking device is energised only during the spin-drying cycle when the drum is
rotating very fast and/or in those machines which have a hot-drying cycle.
The device consists of a box 40 with external couplings 41 and 42 which are
firmly mounted on the protusions 43 and 44 provided on the outside oî the box 1 of
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the door-locking device. The box 40 contains a microswitch constituted by a fixed
contact 45 which has an external prolungation with connection male contact 48 and
push-button 49 which acts on the mobile contact plate 47.
The push-button 49 runs inside 9 hollow cylindrical housing 50 and, therefore,
it can be outside the box 40. In correspondence, the box 1 of the door-locking device
has a hole 51 which accepts the aPoresaid hollow cylindrical housing 50 so that the
push-button 49 can penetrate into box 1 and come into contact with the sliding bar
15 of the door-locking device.
As has already been said, the sliding bar 15 has a notch 20. When at rest, with
the machine off and the door open, the push-button 49 descends to rest on this and,
in this position, the microswitch opens contacts 45-~ as can be seen in figure 1.
When the door is closed, as in figure 3, the rod 15, draws back because of the thrust
exercised on its eyelet 16 by the hook 100 of the door-latch, (see figure 3) andmoves the push-button 49 upwards, closing the circuit. Thus the second phase of the
supply current of the working parts of the machine can flow through contacts 46, 45,
47, 48 in spite of the fact that the door-locking device is operating, and in this
condition the door can be opened during working, and this door opening rP-opens
contacts 45-47 and stops the working parts.
Obviously, this can only happen during the washing and/or drying cycles in
which the second phase of the current is supplied by the programme to the workislg
parts of the machine through connection male contacts 46-48 while, during the spin-
drying cycle which involves high speed rotation of the drum and inertial rotation,
the second phase of the current is Ied to the working parts of the machine through
the connection male contacts 9-11.
